A current detection device configured to detect a load current in a house, a factory, an office, or the like is conventionally known. The current detection device includes, for example, a primary conductor configured to produce a magnetic field when a load current flows therethrough, and a magneto-electric convertor configured to detect the magnetic field produced by the primary conductor (see, for example, Patent Literature 1).
The magneto-electric convertor is formed of a coil formed by winding a conducting wire, such as an enamel wire, around a donut-shaped magnetic core called a toroidal core. Winding the conductive wire around the magnetic core takes a lot of work, and therefore poses a problem of increasing the costs of the current detection device.
To overcome such a problem, Patent Literature 2 discloses a current detection device including a primary conductor configured to produce a magnetic field which is in direct proportion to a measured current, multiple coil portions configured to detect the magnetic field produced by the primary conductor 11, and support portions made of a magnetic material, configured to support the multiple coil portions, and connected to the multiple coil portions in series magnetically with wires, the coil portions and the support portions being provided around the primary conductor. The current detection device is configured to output electric signals from output terminals through the wires, the electric signals being generated by the multiple coil portions based on the magnetic field produced by the primary conductor.
FIG. 1 is a schematic diagram showing the configuration of a conventional, general current detection device, like the one disclosed by Patent Literature 2. This current detection device includes a primary conductor 11 configured to produce a magnetic field in accordance with the magnitude of a measured current, a first coil 12 and a second coil 13 configured to detect the magnetic field produced by the primary conductor 11, and a first magnetic body 14 and a second magnetic body 15 configured to support and magnetically short-circuit the first coil 12 and the second coil 13, the first and second coils 12 and 13 and the first and second magnetic bodies 14 and 15 being provided around the primary conductor 11. The current detection device is configured to output an electric signal generated by the first coil 12 based on the magnetic field produced by the primary conductor 11 from an output terminal 17 through a wire and to output an electric signal generated by the second coil 13 based on the magnetic field produced by the primary conductor 11 from an output terminal 18 through a wire.